Liquid fuel pumps for internal combustion engines



22,1963 K. A. w. KEMP 3,107,651

LIQUID FUEL PUMPS FOR INTERNAL COMBUSTION ENGINES Filed July 23, 1962 s Sheets-Sheet 1 Oct. 22, 1963 K. A.- w. KEMP 3,107,661

LIQUID FUEL PUMPS FOR INTERNAL COMBUSTION ENGINES Filed July 23, l962 5 Sheets-Sheet 2 06k 22, I LIQUID FUEL PUMPS FOR INTERNAL COMBUSTION ENGINES Filed July 23, 1962 K; A; w. KEMP 5 Sheets-Sheet 3 Get. 22, 1963 K. A.- w. KEMP 3,107, 6

LIQUID FUEL PUMPS FOR INTERNAL COMBUSTION ENGINES Filed July 23, 1962 5 sheets sheet 4 K. A. W. KEMP Oct. 22, 1963 3,107,661

LIQUID F'EJEL PUMPS FOR INTERNAL COMBUSTION ENGINES Filed July 25, 1962 5 Sheets-Sheet 5 United States Patent O 3,107,661 LIQUID FUEL PUMPS FOR INTERNAL COMBUSTION ENGINES Kenneth Albert Walters Kemp, Ealing, London, England, assignor to C.A.V. Limited, London, England Filed July 23, 1962, Ser. No. 211,731 6 Claims. (El. 123-139) This invention relates to liquid fuel pumps for internal combustion engines and of the kind comprising a body part, a rotary distributor in the body part, a head formed or secured at one end of the distributor, said head having formed therein a transverse bore, at least one plunger in the bore, an annular cam surrounding the head whereby inward movements will be imparted to the plunger as the head rotates, a longitudinal passage in the distributor in communication with said bore, a delivery passage in the distributor in communication with the longitudinal passage, a plurality of delivery ports in the body part with which the delivery passage is adapted to register in turn as the distributor rotates, and feed means for feeding fuel to the longitudinal passage to move the plunger out wardly.

The object of the invention is to provide a convenient form of such a pump whereby the quantity of fuel delivered may be varied and the timing of its delivery may be varied automatically to accord with conditions under which the engine is operating.

According to the invention a pump of the kind specified comprises in combination an axially movable shuttle in the longitudinal passage in the distributor, means for limiting axial movement of the shuttle, a pair of cylinders in the body part, a pair of pistons in the cylinders respectively, two series of angularly spaced passages in the distributor, said two series of passages being in communication with the longitudinal passage at positions beyond opposite limit poistions of the shuttle respectively, and being adapted to register in turn respectively with one pair of ends of the pair of cylinders whilst the delivery passage is out of register with the delivery ports, further ways in the distributor whereby said one pair of ends of the pair of cylinders are placed in communication with said feed means whilst the delivery passage is in register with any of the delivery ports, and whereby the opposite ends of the pair of cylinders are placed in communication with the said feed means whilst the delivery passage is out of register with the delivery ports, a spill passage in the distributor arranged to be uncovered by the shuttle at the end of its permitted movement in a direction towards the delivery passage, means for controlling the permitted movement of the one piston to determine the quantity of fuel fed to the engine, and means for controlling the permitted movement of the other piston to control the timing of injection.

In the accompanying drawings:

FIGURE 1 is a part sectional side elevation on the line 1-4 of FIGURE 2 of one example of a liquid fuel pump in accordance with the invention showing the parts of the pump at one position during the cycle of operation,

FIGURE 2 is a section on the line 2-2 of FIGURE 1,

FIGURE 3 is a section on the line 33 of FIGURE 2,

FIGURE 4 is a section on the line 4-4 of FIGURE 1,

FIGURE 5 is a section on the line 5-5 of FIGURE 1,

FIGURE 6 is a fragmentary section on the line 6-6 of FIGURE 1,

FIGURE 7 is a section on the line 77 of FIGURE 1,

FIGURE 8 is a part sectional side elevation on the line 8-8 of FIGURE 9 showing the parts of the pump in another position during the cycle of operation,

FIGURE 9 is a fragmentary section on the line 99 of FIGURE 8,

answer FIGURE 10 is a fragmentary section on the line 1019 of FIGURE 9,

FIGURE 11 is a fragmentary section on the line 11-11 of FIGURE 8,

FIGURE 12 is a fragmentary section on the line 12-12 of FIGURE 8,

FIGURE 13 is a fragmentary section on the line 13--13 of FIGURE 8 and FIGURE 14 is a fragmentary section on the line 1414 of FIGURE 8.

Referring to the drawings there is provided a body part 20 which at one end contains a feed pump 21. This pump has an inlet 22 and an outlet formed in the body part, the inlet and outlet being interconnected by a springloaded relief valve (not shown) which regulates the pressure which is generated by the pump to a pressure which varies with the speed of the pump.

At the other end of the body part is contained an injec tion pump which includes -a head 23 having formed in it a diametrically disposed bore 24. In the bore are a pair of reciprocable plungers 25 which, as the head rotates, are adapted to be moved inwardly at an appropriate timing by the interaction of rollers 26 at their outer ends with a surrounding annular cam 27.

The rotary parts of the feed and injection pumps are interconnected by a cylindrical distributor 28 and are adapted to be driven as a unit by the engine with which the pump is to be associated. In the distributor 28 is formed an axial passage 29 which at one end is in communication with the bore 24 in the head 23, and which at its opposite end is in communication with a radially extending delivery passage 30 formed in the distributor and adapted to register in turn, as the distributor rotates, with a plurality of angul-arly spaced delivery ports 31 in the body part; there being as many delivery ports as there are cylinders in the engine with which the pump is associated. In the present example the pump is intended for use with a four cylinder engine and there are therefore four delivery ports which are adapted for connection to injection nozzles associated with four cylinders respectively.

In the axial passage 2? in the distributor 28 is an axially movable shuttle 3-2, movement of which is limited by means of a pair of stems 33, 34 extending into the pars sage from opposite ends. Moreover, in the distributor are formed two series of four equiangularly spaced radial passages extending from the axial passage. The first series of passages 35 open into the axial passage 29 at a position such that they are partially uncovered by the shuttle 32 when the latter is at the extreme limit of its travel towards the delivery passage 30, whilst the second series of passages 36 open to the axial passage at a position such that they are partially uncovered by the shuttle when it is at the extreme limit of its travel towards the bore 24 in the head. Furthermore, the angular position of the passages 35 and 36 is the same. Between the two series of passages 35, 36 there is formed in the periphery of the distributor 28 a circumferentially extending groove 37 which is in communication with the outlet of the feed pump through a feed passage 33 in the body part 20. Extending from the groove 37 is at least one radial spill passage 39 extending into the axial passage and arranged to be uncovered by the shuttle 32 when at the limit of its travel towards the delivery passage 30. Also extending from the groove 37 are four equiangularly spaced longitudinally extending grooves 40 in the periphery of the distributor, these grooves being angularly spaced from the passages 35, 36 by 45.

Angularly displaced from grooves 40 by 45 is a further series of longitudially extending grooves 41 in the periphery of the distributor. The grooves 41 are disposed axially between the series of radial passages 35 and Patented Oct. 22, 1&63

the delivery passage 3% in the distributor, and are disposed axially so as to overlap the longitudinal grooves 40 by a small amount. Furthermore, the longitudinal grooves 41 are in communication with a circumferential groove 42 in the distributor which is in communication with a passage 43 in the body part leading to the inlet side of the feed pump 21.

In the body part are formed a pair of cylinders 44, 45 the axes of which extend parallel to one another and radially relative to the distributor. Moreover, in the pair of cylinders are a pair of axially movable pistons 46, 47 respectively. At the inner end of the cylinder 44 is a port 48 with which the passages 36 and the longitudinal grooves 40 are adapted to register alternately and in turn as the distributor rotates, whilst at the inner end of the cylinder 45 is a port 49 with which the passages 3'5 and the longitudinal grooves 40 are adapted to register alternately and in turn as the distributor rotates. Moreover, in communication with the outer ends of both cylinders is a passage 50 in the body part. This passage, as the distributor rotates, is adapted to register alternately and in turn with the overlapping end portions of the longitudinal grooves 46, 41. The operation of the pump as so far described is as follows:

Assuming that the plungers 25 of the injection pump are moved apart, and that the shuttle 32 is against the stop 33, then as the plungers are moved inwardly the displacement of fuel from the bore 24 will cause the shuttle to be moved towards the stop 34 thereby displacing fuel trout the axial passage 29 at the opposite side of the shuttle through the delivery passage 30 to the appropriate delivery port 31, any excess fuel remaining in the bore after the shuttle has partaken of its full stroke being discharged through the spill passage 39. Whilst the delivery passage 3% is in register with any one of the delivery ports 31 fuel is also being fed from the feed pump 21 to the inner ends of the cylinders 44, 45 by way of the groove 37 and one of the grooves 40. Meanwhile fuel can escape from the outer ends of the cylinders 44, 45 through one of the grooves 41 by way of passage 50. At a position of the distributor 45 subsequently, one of the longitudinal grooves 40 is placed in communication with the outer ends of the cylinders 44, 45, by way of passage 50 whilst their inner ends are in communication respectively with one of the radial passages 36, 35. As a result fuel fed by the feed pump to the outer ends of the, cylinders will cause the pistons to move inwardly. Fuel from the cylinder 45 is fed to the axial passage 39 in the distributor, and will move the shuttle towards the bore 24 in the head by an amount dependent upon the quantity of fuel fed from the cylinder 45. This amount determines the quantity of fuel fed to the engine on the next injection stroke. Fuel fed to the side of the shuttle from the cylinder 44 will cause the plungers 25 of the injection pump to be moved outwardly to an extent dependent upon the quantity of fuel fed. This quantity in turn determines the timing of the injection, since the further the plungers are moved outwardly the sooner in the cycle will the rollers .26 strike the cam 27 and start to move. inwardly.

Outward movements of the pistons 46, 47 within their cylinders is determined by adjustable stops 51, 52 in the 'form of cylindrical plungers fitting within cylindrical bores coaxially disposed with respect to the cylinders respectively. The stop 52 for the piston 47 at its outer end bears directly against a face cam 53 which can be moved angularly by a control lever 54 extending from the body part, this control lever being operable by the driver. The stop 51 for the piston 46 bears upon the face cam 53 through the intermediary of a wedge 55 which is movable laterally relative. to the axis of the stop. The wedge is pivotally connected to a springloaded piston 56 contained in a cylinder 57 extending at right angles to the axis of the stop, and the end of this cylinder remote from the wedge is subjected to the output pressure of the feed pump through passages 58 in the body part. The arrangement is such that the output pressure of the feed pump 21, which varies with speed, acts against the spring acting on the piston 56 and thereby determines the position of the wedge. By this arrangement the position of the control lever which may be directly operable by the driver, or under the control of a driver adjustable governor, determines the quantity of 'fuel which is fed to the engine on each injection stroke, and also adjusts the timing of the injection to accord with this setting. However, a further setting of the timing of injection is elfected automatically to accord with the actual engine speed by means of the wedge 55. A manually adjustable stop 60 for cooperation with the control lever may be provided for determining the maximum quantity of fuel which can be fed to the engine, and a further manually adjustable screw 59 may be provided for determining the axial setting of the face cam 53 so as to enable the pump to be adjusted for a particular engine.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

l. A liquid fuel pump of the kind specified for a multicylinder internal combustion engine, and comprising in combination a hollow body part provided with a fuel feed passage, a cylindrical distributor rotatably supported within a complementary portion of said hollow body part, and provided with an axial passage, a head rig-idly united with one end of said cylindrical distributor, and provided with a transverse bore in communication with one end of said axial passage, at least one plunger slidably supported within said transverse bore, an annular cam which surrounds said head, and which serves, during rotation of said cylindrical distributor, to impart inward movements to said plunger, a delivery passage which is disposed radially in the end portion of said distributor remote from said head, and which at its inner end cornmunicates with said axial passage, a plurality of delivery ports which are provided in said body part, and with which the outer end of said delivery passage registers in turn as said distributor rotates, feed means for supplying fuel under pressure to the fuel feed passage in said body part, an axially movable shuttle slidably supported in said axial passage, means for limiting axial movement of said shuttle in opposite directions, first and second parallel cylinders formed in said body part, and extending radially outwards relative to the axis of said distributor, a pair of pistons slidably mounted respectively in said cylinders, a first series of angularly spaced passages disposed radially in said distributor at positions in which said first series of angularly spaced passages communicate with said axial passage at positions beyond the limit position of said shuttle nearest to said delivery passage, and, during rotation of said distributor, the outer ends of said first series of angularly spaced passages register in turn with the inner end of the first cylinder whilst said delivery passage is out of register with all of said delivery ports, a second series of angularly spaced passages disposed radially in said distributor at positions in which said second series of angularly spaced passages communicate with said axial passage at positions beyond the limit position of said shuttle nearest to said transverse bore, and, during rotation of said distributor, the outer ends of said second series of angularly spaced passages register in turn with the inner end of the second cylinder whilst said delivery passage is out of register with all of said delivery ports, further passages formed in said distributor and said body part at positions for enabling the inner ends of said cylinders to communicate with said feed passage through said further passages in said distributor whilst said delivery passage is in register with any one of said delivery ports, and for enabling the outer ends of said cylinders to communicate with said feed passage whilst said delivery passage is not in register with any one of said delivery ports, a spill passage in said distributor at a position in which said spill passage is uncovered by said shuttle when the latter reaches the end of its movement towards said delivery passage, and adjustable means for variably limiting outward movements of said pistons.

2. A liquid fuel pump according to claim 1, wherein said adjustable means for variably limiting the outward movements of said pistons comprise in combination a pair of parallel cylindrical stops which are coaxial respectively with said pistons, and which are slidably supported respectively within a pair of bores formed in said body part adjacent the outer ends of said cylinders, and an angularly adjustable cam plate mounted to act on the ends of said stops remote from said pistons to vary the axial positions of said stops.

3. A liquid fuel pump according to claim 2, wherein said further passages formed in said distributor comprise a plurality of longitudinal grooves which are formed in the outer periphery of said distributor, and which extend between, and are spaced from, the outer ends of the angularly spaced passages forming said first and second series, and a circumferential groove which is formed in the outer periphery of said distributor, and which establishes communication between said feed passage and said longitudinal grooves.

4. A liquid fuel pump according to claim 3, wherein said circumferential groove establishes communication between said spill passage and said feed passage.

5. A liquid fuel pump according to claim 2, and having means which is responsive to the pressure of fuel supplied to said feed passage by said feed means, and which .co-operates with said angularly adjustable cam plate for varying the axial position of the cylindrical stop coaxial with the piston in said second cylinder.

6. A liquid fuel pump according to claim 5, wherein the means responsive to the pressure of fuel supplied to said feed passage by said feed means comprises in combination a wedge piece interposed between said cam plate and the cylindrical stop coaxial with the piston in said second cylinder, and a spring-loaded piston which is connected to said wedge piece for controlling the position thereof, and which is movable in opposition to its spring loading by the pressure of fuel supplied to said feed passage.

References Cited in the file of this patent UNITED STATES PATENTS 3,035,523 Kemp et a1 May 22, 1962 

1. A LIQUID FUEL PUMP ON THE KIND SPECIFIED FOR A MULTICYINDER INTERNAL COMBUSTION ENGINE, AND COMPRISING IN COMBINATION A HOLLOW BODY PART PROVIDED WITH A FUEL FEED PASSAGE, A CYLINDRICAL DISTRIBUTOR ROTATABLY SUPPORTED WITHIN A COMPLEMENTARY PORTION OF SAID HOLLOW BODY PART, AND PROVIDED WITH AN AXIAL PASSAGE, A HEAD RIGIDLY UNITED WITH ONE END OF SAID CYLINDRICAL DISTRIBUTOR, AND PROIVIDED WITH A TRANSVERSE BORE IN COMMUNICATION WITH ONE END OF SAID AXIAL PASSAGE, AT LEAST ONE PLUNGER SLIDABLY SUPPORTED WITHIN SAID TRANSVERSE BORE, AN ANNULAR CAM WHICH SURROUNDS SAID HEAD, AND WHICH SERVES, DURING ROTATION OF SAID CYLINDRICAL DISTRIBUTOR, TO IMPART INWARD MOVEMENTS TO SAID PLUNGER, A DELIVERY PASSAGE WHICH IS DISPOSED RADIALLY IN THE END PORTION OF SAID DISTRIBUTOR REMOTE FROM SAID HEAD, AND WHICH AT ITS INNER END COMMUNICATES WITH SAID AXIAL PASSAGE, A PLURALITY OF DELIVERY PORTS WHICH ARE PROVIDED IN SAID BODY PART, AND WITH WHICH THE OUTER END OF SAID DELIVERY PASSAGE REGISTERS IN TURN AS SAID DISTRIBUTOR ROTATES, FEED MEANS FOR SUPPLYING FUEL UNDER PRESSURE TO THE FUEL FEED PASSAGE IN SAID BODY PART, AN AXIAL MOVABLE SHUTTLE SLIDABLY SUPPORTED IN SAID AXIAL PASSAGE, MEANS FOR LIMITING AXIAL MOVEMENT OF SAID SHUTTLE IN OPPOSITE DIRECTIONS, FIRST AND SECOND PARALLEL CYLINDERS FORMED IN SAID BODY PART, AND EXTENDING RADIALLY OUTWARDS RELATIVE TO THE AXIS OF SAID DISTRIBUTOR, A PAIR OF PISTONS SLIDABLY MOUNTED RESPECTIVELY IN SAID CYLINDERS, A FIRST SERIES OF ANGULARLY SPACED PASSAGES DISPOSED RADIALLY IN SAID DISTRIBUTOR AT POSITIONS IN WHICH SAID FIRST SERIES OF ANGULARLY SPACED PASSAGES COMMUNICATE WITH SAID AXIAL PASSAGE AT POSITION BEYOND THE LIMIT POSITION 